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PubMed2002

Social disadvantage: its impact on the use of Medicare services related to diabetes in NSW.

OBJECTIVE: To use Medicare data to examine the impact of social disadvantage on the use of health services related to diabetes. METHOD: Information on number of diabetic individuals and number of services for select Medicare item codes were retrieved by New South Wales postcodes using a Health Insurance Commission data file. The postcodes were graded into quintiles of social disadvantage. RESULTS: People at most social disadvantage were significantly less likely to be under the care of a general practitioner (adjusted OR 0.41; 95% CI 0.40-0.41) or consultant physician (adjusted OR 0.50; 95% CI 0.48-0.53), despite this group having the highest prevalence of diabetes. The difference in attendance to other specialists was less marked but nevertheless significant (adjusted OR 0.71; 95% CI 0.68-0.75). Once under a doctor's care, patients at most disadvantage were slightly more likely to undergo HbA1c or microalbuminuria estimation (adjusted OR 1.04; 95% CI 1.00-1.10 and adjusted OR 1.22; 95% CI 1.12-1.33, respectively) but were less likely to undergo lipid or HDL cholesterol estimation (adjusted OR 0.81; 95% CI 0.48-0.53 and adjusted OR 0.85; 95% CI 0.79-0.90, respectively). CONCLUSION: While access to medical care is decreased for people at most social disadvantage, once under a doctor's care they receive a level of monitoring that is relatively equal to that provided to people less disadvantaged. IMPLICATION: Strategies are required to ensure equal access to medical services for all persons with diabetes, especially for persons who are at most social and medical disadvantage.

Clinical Chemistry Tests↗

PubMed1999

Lack of significant cross-reactivity between Leishmania serology and mycobacteriosis in patients infected with HIV-1.

OBJECTIVE: To determine the existence of cross-reactions between Leishmania serology and mycobacteriosis in patients infected with HIV-1. PATIENTS AND METHODS: HIV-positive individuals, with culture-proven episodes of tuberculosis or disseminated Mycobacterium avium complex (MAC) infection, were identified from the data files of our microbiology laboratory. Patients were included if leishmania serology had been performed within a period of 2 months before and 1 month after the diagnosis of mycobacterial disease. RESULTS: We identified 106 cases of tuberculosis and 38 of disseminated MAC infection with concomitant leishmania serology in HIV-infected individuals. Among them, only two cases (1.8%), both with tuberculosis and without visceral leishmaniasis, showed positive leishmania serology. The two cases are discussed. CONCLUSIONS: We conclude that, in spite of its low sensitivity, serology is a useful diagnostic tool in co-infected patients, mainly because of its high specificity and the low rate of cross-reactivity with two of the most frequent causes of fever of unknown origin in HIV-positive patients from our area.

Journal Article↗

PubMed1996

Clinical application of a microcomputer system for analysis of monophasic action potentials.

UNLABELLED: Computerized analysis of monophasic action potentials (MAPs) has rarely been reported in clinical setting. We developed a computer system featuring on-line acquisition and user-monitored automatic measurement of multichannel MAPs with the capability of manual corrections. This system has been used in 34 patients in whom two-channel MAPs and 1-lead ECG were digitized during sinus rhythm, pacing, and programmed stimulation (PS). In total, 41, 413 MAPs in 212 data files were measured. The correct determination rate was 100% for MAP onset and plateau, 99.78% (95.76% during PS) for MAP baseline, and 99.96% (54.29% during PS) for QRS onset. The comparison between the computerized and manual measurements in 292 MAPs showed that the former highly agreed with the latter, with the limits of agreement, defined as mean difference +/- 2 SD, being from -4.8-4.9 ms for activation time and from -4.1-6.0 ms for MAP duration measurements. Using this system, two-channel MAPs of more than 300 consecutive beats can be measured in a few minutes, which made it possible to determine the steady state of MAP duration individually, and evaluate the MAP changes during intervention in detail. The clinical routine procedure for testing the effective refractory period and several new MAP parameters were also evaluated using this system. CONCLUSION: The MAP measurement using this computer system is reliable, rapid and accurate; it can therefore replace the manual method and provide more useful information for clinical research.

Action Potentials↗

PubMedDate not supplied

Urinary incontinence in pregnancy and the puerperium.

OBJECTIVE: To describe the incidence of urinary incontinence (UI) during pregnancy and the puerperium and to identify potential contributing factors. DESIGN: A descriptive correlational design, using participant interviews and reviews of the existing medical records to determine the incidence of UI in pregnancy and the puerperium and to examine relationships between and among several variables. The variables included parity, episiotomy, use of forceps/vacuum extractor, type of anesthesia, prolonged Stage II labor, and race. Data were collected via two personal interviews and review of medical records. The first interview was conducted during the recruitment of each participant; the second was a telephone interview conducted 4 to 6 weeks postpartum. Data collected from the medical records included obstetric history, weeks of gestation, and estimated date of delivery. Data were entered into data files for analysis with SPSS 8.0 and summarized with descriptive statistics. SETTING: A secluded area of a university teaching hospital prenatal clinic. PARTICIPANTS: A convenience sample of 50 pregnant women, at least 18 years old, who received their care at a large university hospital prenatal clinic in the southeastern part of the United States. RESULTS: First Interview (N = 50). More than half (62%; n = 31) of the sample reported some degree of involuntary urine loss during their pregnancy. The racial distribution of those reporting UI was the following: white (70%; 21 out of 30); African American (44%; 8 out of 18); Hispanic/Asian (100%; n = 2). Among the participants who experienced UI (n = 31), 76% (n = 23) reported that their health care provider never asked if they were experiencing any UI symptoms. Second Interview (n = 24). Only 48% of the initial participants could be contacted for the second interview because of changes in residence or telephones being disconnected with no forwarding number. Of the women in this sample who reported UI during the first interview (59%; n = 14), 7 (50%) continued to experience UI 4 to 6 weeks postpartum. The 2 remaining participants who reported UI 4 to 6 weeks postpartum (22%) had not experienced UI during pregnancy. Of the participants experiencing postpartum UI, 77% (n = 7) were white. Almost half of the participants with postpartum UI were ages 35 or older (44%; n = 4). Among the participants reporting episiotomy (n = 4), 3 (75%) reported having UI 4 to 6 weeks postpartum. CONCLUSIONS: Study results support the conclusion that childbirth, specifically vaginal birth, is a major factor in developing UI in the early postpartum period. Age, race, and use of episiotomy appear to be contributing risk factors.

Adult↗

PubMed1998

Geographic distribution of constipation in the United States.

OBJECTIVE: Despite its frequent occurrence, the etiology of constipation has remained poorly understood. The influence of widely accepted risk factors such as inadequate dietary fiber intake, immobility, insufficient fluid intake, and poor muscle tone is unclear. This study examined the geographic distribution of constipation among Medicare beneficiaries to identify potential environmental risk factors. METHODS: All Medicare beneficiaries with a diagnosis of constipation were extracted from the total Health Care Financing Administration data file of 1987 and stratified by sex, race, and state of residence. The population of each state by sex, race, and age >65 yr served as the denominator to calculate sex- and race-specific morbidity rates. RESULTS: A distinct geographic distribution was observed. When stratified by individual states, hospital discharges for constipation were more common in rural as compared with urban states. Constipation also appeared to be more common in northern and in poorer states. CONCLUSION: The distinct geographic pattern of constipation suggests the influence of three global environmental factors: rural living, colder temperature, and lower socioeconomic status.

Aged↗

PubMed2001

Occupational mortality from inflammatory bowel disease in the United States 1991-1996.

OBJECTIVE: The occupational distribution of inflammatory bowel disease (IBD) may help to shed light on its yet unknown etiology. The U.S. vital statistics offer the opportunity to study cause of death by occupation and industry. METHODS: The numbers of deaths from Crohn's disease and ulcerative colitis were retrieved from the computerized 1991-1996 data files of the National Center for Health Statistics. Deaths were grouped by gender, ethnicity, disease type, occupation, and industry. Mortality by occupation and industry were expressed as proportional mortality ratio (PMR), adjusted for gender and ethnicity. RESULTS: Between 1991 and 1996, 2399 subjects died from Crohn's disease and 2419 subjects died from ulcerative colitis. Significant correlations were found between the PMR values of ulcerative colitis and Crohn's disease regarding their distribution by occupation, r = 0.36 and p < 0.05, as well as by industry, r = 0.37, p < 0.01. IBD mortality by occupation was significantly reduced among farmers (PMR: 70, 95% confidence interval [CI]: 42-97), mining machine operators (31, 95% CI: 0-74), and laborers (71. 95% CI: 45-98). A nonsignificant increase was found among sales persons (117, 95% CI: 95-139) and secretaries (122, 95% CI: 83-161). IBD mortality by industry was significantly reduced in agricultural production of livestock (39, 95% CI: 1-78), mining (46, 95% CI: 9-83), grocery stores (55, 95% CI: 17-94), and work in private households (64, 95% CI: 30-97). A nonsignificant increase was found in food production (128, 95% CI: 74-182), investment and insurance business (137, 95% CI: 77-198), and administration (122, 95% CI: 81-163). CONCLUSIONS: IBD mortality is low in occupations associated with manual work and farming and relatively high in sedentary occupations associated with indoor work. Crohn's disease and ulcerative colitis show a similar distribution.

Aged↗

PubMed2001

The comorbid occurrence of other diagnoses in patients with ulcerative colitis and Crohn's disease.

OBJECTIVES: The comorbidity between inflammatory bowel disease (IBD) and other diagnoses may help to shed light on the etiology and pathophysiology of IBD. The US Vital Statistics offer the opportunity to study causes of death broken down by comorbid disease associations. The aim of this study was to analyze the presence of comorbid conditions in persons who died from ulcerative colitis or Crohn's disease. METHODS: The numbers of deaths from ulcerative colitis and Crohn's disease were retrieved from the computerized 1991-1996 data files of the National Center for Health Statistics. Comorbid associations between other diagnosis and ulcerative colitis or Crohn's disease were expressed as age-, gender-, and race-standardized proportional mortality ratios. RESULTS: Ulcerative colitis and Crohn's disease showed, in general, similar patterns of comorbidity. Both diseases were associated with similar sets of GI complications, such as intestinal obstruction and stasis, mucosal inflammation and infection, vascular complications, and complications related to fistula and abscess formation. Extraintestinal complications of both IBD involved disorders of the hepatobiliary system, urinary system, and various coagulopathies. Ulcerative colitis alone was found to be associated with Hirschsprung's disease and schizophrenia, whereas Crohn's disease alone was found to be related with osteoporosis and amyloidosis. CONCLUSIONS: No completely unexplained or hitherto undescribed association was revealed. The numerous intestinal and extraintestinal complications associated with IBD serve as a reminder of the systemic nature and the resultant clinical severity of both ulcerative colitis and Crohn's disease.

Aged↗

PubMed1999

Psychopathy and psychopathological profiles in prisoners on remand.

A total of 178 Danish male remand prisoners were examined using comprehensive interviews and questionnaires on psychopathological, personality and social measures, and file data. These data were compared with scores on the Hare Psychopathy Checklist - Revised (PCL-R). Subjects were divided into four groups according to quartile PCL-R scores. In general there were high rates of psychiatric morbidity in all PCL-R quartile groups. The medium-high scorers represent a more vulnerable group with a high prevalence of dependence disorders, relatively high neuroticism score and relatively high prevalence of neurotic and stress-related disorders. The high scorers were more psychosocially maladjusted, had more often made previous suicidal attempts, and had a higher psychoticism score. Chronic psychotic disorders did occur, mostly in the high-scoring group. The population had lower scores on the PCL-R than in most previous studies, suggesting a lower prevalence of psychopathic features among Danish criminals and possibly a lower cut-off point when using the PCL-R as a categorical measure. Both findings are consistent with the results of other European studies. Further studies on cross-cultural differences with regard to PCL-R psychopathic features and on psychic vulnerability related to PCL-R scores and factor 1/factor 2 of the PCL-R are suggested.

Adolescent↗

PubMed1985

Score system for behaviour of radiologically diagnosed approximal carious lesions.

The evolution of systems which monitor changes in the severity of approximal carious lesions diagnosed from serial bitewing radiographs is reviewed. These systems derive a 'score' for each individual lesion based upon the extent of its progression. A new lesion behaviour score system is described which, unlike its predecessors, allows both lesion regression and data from partially overlapped but readable surfaces to contribute to scores. It employs scoring codes from a previously proposed standardized grading system which is compatible with WHO recommendations for grading clinical caries. The score system is designed to be used as a computer program capable of running on a variety of readily available microcomputers; this allows the incorporation of a flexible range of additional options which use the standard data files to calculate scores according to differing conventions. These accommodate variations in: the threshold at which restorative intervention is practiced, the treatment of reversals of caries diagnosis, the threshold of caries diagnosis and the way in which partially overlapped surfaces are scored. These options allow the system to be configured to suit the local needs of different investigations and workers, and also permit the study of the effects of these various methodologies.

Dental Caries↗

PubMed2003

Trends in childhood drowning on U.S. farms, 1986-1997.

Computerized mortality data files from the National Center for Health Statistics were analyzed to describe childhood farm drowning from 1986 through 1997. Farm drowning rates were compared to the U.S. unintentional youth drowning rates for the same period. The denominator for the calculation of rates was derived from a series of farm youth estimates published by the Bureau of Census. There were 378 childhood farm drowning cases during the study period, for an average annual rate of 2.3 deaths per 100,000 farm youth resident years. This rate is comparable to unintentional drowning rates for U.S. youth (2.2/100,000 population). Fatality rates declined 28% from 1986 through 1997 (p = .0024) for farm youth and 41% for U.S. youth (p = .0001). An average 32 farm drowning incidents occur to youth annually, making drowning a legitimate concern for farm residents and visitors.

Accidents↗

PubMed2005

Where a cancer patient dies: the effect of rural residency.

CONTEXT: Surveys indicate 50% to 80% of cancer patients would choose to die at home if possible, although far fewer actually do. In Nova Scotia (NS), cancer deaths occurring out-of-hospital increased from 19.8% in 1992 to 30.2% in 1997. The impact of rural residency on this trend has not been studied. PURPOSE: To determine the association between dying of cancer in a rural locale and the likelihood of it being an out-of-hospital death. METHODS: Secondary analysis of linked population-based administrative health data files. Subjects were all Nova Scotians who died of cancer from 1992 to 1997. Measures included location of death, dichotomized as a hospital death or an out-of-hospital death; and urban-rural residency, using an enumeration area urban-rural indicator created from postal code information adjusted for individual characteristics. RESULTS: Of the 13,652 total cancer deaths, 6171 occurred in rural NS, of whichl 1471 (23.8%) died out-of-hospital. Out-of-hospital deaths in rural NS increased from 16.2% in 1992 to just over 27% in 1997. Compared with urban cancer patients, the adjusted odds of an out-of-hospital death in rural NS was lower (adjusted odds ratio, 0.87; 95% confidence interval, 0.79-0.95). CONCLUSIONS: There was an increasing trend during the 1990s for cancer patients to die out-of-hospital. Compared with their urban counterparts, patients in rural areas were less likely to do so. Those with cancer living in the rural setting who wish to die at home may face unique challenges.

Adult↗

PubMed1993

Correlation of primate red nucleus discharge with muscle activity during free-form arm movements.

1. We recorded from 239 neurons located in the magnocellular division of the red nucleus of four alert macaque monkeys. At the same time, we recorded electromyographic (EMG) signals from as many as twenty electrodes chronically implanted on muscles of the shoulder, arm, forearm and hand. We recorded EMG signals for periods ranging from several months to a year. 2. The monkeys were trained to perform three free-form food retrieval tasks, each of which activated all of the recorded muscles and most of the neurons. The 'prehension' task required simply that the monkey grasp a piece of food from a fixed point in space. The 'barrier' task required the monkey to reach around a small barrier to obtain the food, and the 'Kluver' task required that food be removed from small holes. During the prehension task, we found approximately equal numbers of neurons that were strongly active while the hand was being moved toward the target (70% of units), and while the food was being grasped (60%). Relatively few units were active as the hand was returned to the mouth (15%). 3. Data files of 1-2 min duration were collected while the monkey performed a single behavioural task. Whenever possible, we recorded files for all three tasks from each neuron. For each file we calculated long time-span analog cross-correlations (+/- 1.28 s) between instantaneous neuronal firing rate and each of the full-wave rectified, low-pass filtered EMG signals. We used the peak correlation and the time of the peak as two summary measures of the functional relation between modulation of neuronal activity and EMG. 4. The magnitude of the strongest correlations was between 0.4 and 0.5 (normalized to a perfect correlation of +/- 1.0). Distal muscles were the most frequently correlated, and extensors were more frequently correlated than flexors. For all monkeys, the lags for well correlated muscles were distributed broadly about a uni-modal value near 0 ms. Eighty five per cent of the correlations larger than or equal to 0.25 had peaks between -150 and 200 ms. 5. The activity of each neuron was represented in a muscle co-ordinate system by an n-dimensional 'functional linkage vector', each element of which was the peak correlation with one of n muscles. The vector for any given neuron points in a particular direction in muscle space, depending on the similarity between the activity of the neuron and the activity of each muscle.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed2003

Dependence of fluence errors in dynamic IMRT on leaf-positional errors varying with time and leaf number.

In d-MLC based IMRT, leaves move along a trajectory that lies within a user-defined tolerance (TOL) about the ideal trajectory specified in a d-MLC sequence file. The MLC controller measures leaf positions multiple times per second and corrects them if they deviate from ideal positions by a value greater than TOL. The magnitude of leaf-positional errors resulting from finite mechanical precision depends on the performance of the MLC motors executing leaf motions and is generally larger if leaves are forced to move at higher speeds. The maximum value of leaf-positional errors can be limited by decreasing TOL. However, due to the inherent time delay in the MLC controller, this may not happen at all times. Furthermore, decreasing the leaf tolerance results in a larger number of beam hold-offs, which, in turn leads, to a longer delivery time and, paradoxically, to higher chances of leaf-positional errors (< or = TOL). On the other end, the magnitude of leaf-positional errors depends on the complexity of the fluence map to be delivered. Recently, it has been shown that it is possible to determine the actual distribution of leaf-positional errors either by the imaging of moving MLC apertures with a digital imager or by analysis of a MLC log file saved by a MLC controller. This leads next to an important question: What is the relation between the distribution of leaf-positional errors and fluence errors. In this work, we introduce an analytical method to determine this relation in dynamic IMRT delivery. We model MLC errors as Random-Leaf Positional (RLP) errors described by a truncated normal distribution defined by two characteristic parameters: a standard deviation sigma and a cut-off value deltax0 (deltaxo approximately TOL). We quantify fluence errors for two cases: (i) deltax0 >> sigma (unrestricted normal distribution) and (ii) deltax0 << sigma (deltax0--limited normal distribution). We show that an average fluence error of an IMRT field is proportional to (i) sigma/ALPO and (ii) deltax0/ALPO, respectively, where ALPO is an Average Leaf Pair Opening (the concept of ALPO was previously introduced by us in Med. Phys. 28, 2220-2226 (2001). Therefore, dose errors associated with RLP errors are larger for fields requiring small leaf gaps. For an N-field IMRT plan, we demonstrate that the total fluence error (if we neglect inhomogeneities and scatter) is proportional to 1/square root of N, where N is the number of fields, which slightly reduces the impact of RLP errors of individual fields on the total fluence error. We tested and applied the analytical apparatus in the context of commercial inverse treatment planning systems used in our clinics (Helios and BrainScan). We determined the actual distribution of leaf-positional errors by studying MLC controller (Varian Mark II and Brainlab Novalis MLCs) log files created by the controller after each field delivery. The analytically derived relationship between fluence error and RLP errors was confirmed by numerical simulations. The equivalence of relative fluence error to relative dose error was verified by a direct dose calculation. We also experimentally verified the truthfulness of fluences derived from the log file data by comparing them to film data.

Humans↗

PubMedDate not supplied

Computational analysis and dosimetric evaluation of a commercial irregular-fields computer program.

The proper evaluation of the accuracy of a new computer program for radiation-therapy dosimetry requires consideration of both the mathematical algorithm used in the program and the performance required in clinical applications. As an example, our evaluation of the irregular-fields dosimetry program currently marketed by SHM for their Rad-8 system is described. The evaluation begins with an explanation of the mathematical computation described. The evaluation begins with an explanation of the mathematical computation method, with emphasis on the points where the calculation differs from previous methods. Next, the procedure for setting up the beam data file is discussed. Finally, a step-by-step procedure is described in which calculated doses are compared with measured doses, using a Varian Clinac-4 with lead flattening filter, and the limits within which a +/- 5% accuracy is attainable are estimated. Some sources of error and areas for possible improvements are mentioned.

Computers↗

PubMedDate not supplied

Specific gamma-ray constant and exposure rate constant of 192Ir.

Calculated values of the 192Ir specific gamma-ray constant, Gamma range from the low value of 3.948 R cm2h-1mCi-1 recommended in NCRP No. 41 to a high of 4.89 R cm2h-1mCi-1. Measured values of Gamma range only from 4.85 to 5.0 Rcm2h-1mCi-1. Discrepancies in reported calculated values exist because the isotope decay scheme and other nuclear spectroscopy data pertinent to these calculations were not well known. Using the 28 gamma rays and relative intensities from the most recent Evaluated Nuclear Structure Data File (ENSDF), Gamma is calculated to be 4.62 +/- 0.05 Rcm2h-1mCi-1 and the exposure rate constant Gamma delta is 4.69 +/- 0.05 Rcm2h-1mCi-1. These new calculations are presented and previously reported values of Gamma and Gamma delta are reviewed.

Gamma Rays↗

PubMedDate not supplied

The specific gamma-ray constant and exposure rate constant of 182Ta.

Reported values of the specific gamma-ray constant gamma for 182Ta range from the original value of 6.1 to 7.692 R cm2h-1mCi-1, recommended in NCRP Report No. 41. The original calculation of gamma was based on inadequate nuclear spectroscopy and decay scheme data. The higher value of gamma occurs because of a computational error in the relative intensity of the 1.2575-MeV gamma ray. Using nuclear spectroscopy data from the most recent Evaluated Nuclear Data File (ENSDF), gamma is calculated to be 6.71 +/- 0.06 R cm2h-1mCi-1 and the exposure rate constant gamma gamma is 6.87 +/- 0.06 R cm2h-1mCi-1. These new calculations are presented and previously reported values of gamma and gamma gamma are reviewed.

Radioisotopes↗

PubMedDate not supplied

The generalized geometry of eye plaque therapy.

A calculation is described that enables the rapid assessment of dose rate at various points of interest within the eye (lens, optic nerve, etc.) for the treatment of choroidal melanoma by plaque therapy. 125I seeds are used as the radiation source. The location of the plaque and its associated seeds relative to the eye (in a Cartesian coordinate system) is determined from the description of the tumor, as drawn and dimensioned on a fundus-view diagram by the ophthalmologist. This requires a computer to numerically solve an equation, which is derived in the framework of spherical geometry. Further results of this calculation yield data files that serve as the input to a conventional brachytherapy treatment planning program. This enables the visualization of the dose distribution within a plane that contains the major axis of the tumor in order to assess the adequacy of the treated volume.

Brachytherapy↗

PubMedDate not supplied

Optimal electron-beam treatment planning for retinoblastoma using a new three-dimensional Monte Carlo-based treatment planning system.

Electron-beam treatment planning for retinoblastoma was investigated and an optimal treatment plan was devised for a particular case using a new three-dimensional Monte Carlo-based treatment planning system known to be capable of correctly predicting dose perturbations caused by body surface obliquities and tissue heterogeneities. Computed tomography (CT) data files were used to construct a three-dimensional eye phantom representing the anatomy of a child's orbit. Dose distributions in sagittal, transverse, and coronal planes were predicted with 1-mm resolution. Study of these distributions led to an optimal treatment plan consisting of an anterior-lateral pair, with the anterior field being a 10-MeV, 30-mm-diam circular field, centrally blocked by a 10-mm-diam lucite lens shield and the lateral field being a 16-MeV, 30 x 25-mm D-shaped field. The anterior field delivers a therapeutic dose to the ora serrata, but it underdoses the posterior retinal surface behind the lens shield; the lateral field provides the necessary boost dose to the posterior retinal surface. An equally weighted combination of the two fields produces a dose distribution in which the entire retinal surface receives a therapeutic dose, with less than 10% of that dose being delivered to the lens, brain, and the contralateral orbit.

Electrons↗